Characterization of deformation microstructure of Mg alloys containing LPSO structure via transmission electron microscopy

形变孪晶中的析出物阻碍位错运动，从而影响材料的力学性能。在此，在原子水平上，我们直接可视化，基底位错滑移剪切变形孪晶内的孪晶堆垛层错（TSFs）的Mg-Zn-Y合金含有长周期堆垛有序（LPSO）结构。富含溶质原子的TSF可以被认为是形变孪晶内部的沉淀物。它们在基面上被单个剪切步骤或多个剪切步骤剪切。微结构指纹，即，基底剪切台阶的宽度使得能够定量评估由于变形孪晶内的基底位错引起的局部和总塑性剪切应变。横向剪切应力能阻止位错滑移，而位错剪切则导致晶格畸变，甚至导致溶质原子在局部相交处重新分布。TSFs与位错的相互作用可以降低位错的运动，从而调节镁合金的力学性能。这些结果为通过剪切相的定制实现镁合金的强韧化提供了一种新的策略。

The precipitates inside deformation twins may block the dislocation motion and consequently affect the mechanical property of materials. Herein, at the atomic level, we directly visualize that the basal dislocation slips shear the twinned stacking faults (TSFs) within the deformation twins in an Mg-Zn-Y alloy containing long-period stacking ordered (LPSO) structures. The TSFs, enriched with solute atoms, could be considered as precipitates inside deformation twins. They are sheared by a single step or multiple shearing steps on the basal plane. The microstructural fingerprints, i.e., the width of basal shearing steps, enable a quantitative assessment of the local and total plastic shear strain due to the basal dislocation within the deformation twins. The TSFs can block dislocation slip, while the dislocation shearing induces large lattice distortion and even solute atoms redistribution at local intersection. The TSFs-dislocation interaction is expected to lower the basal dislocation motion and resultantly modulate the mechanical properties of magnesium alloys. These results may offer a novel strategy for strengthening and toughening magnesium alloys via tailoring the shearable precipitates.